diff --git a/src/api/schema.rs b/src/api/schema.rs
index e01f18af..9274dbcf 100644
--- a/src/api/schema.rs
+++ b/src/api/schema.rs
@@ -251,7 +251,7 @@ impl ArraySchema {
 pub struct ObjectSchema {
     pub description: &'static str,
     pub additional_properties: bool,
-    pub properties: HashMap<&'static str, (bool, Arc<Schema>)>,
+    pub properties: HashMap<&'static str, Arc<Schema>>,
     pub default_key: Option<&'static str>,
 }
 
@@ -278,12 +278,12 @@ impl ObjectSchema {
     }
 
     pub fn required<S: Into<Arc<Schema>>>(mut self, name: &'static str, schema: S) -> Self {
-        self.properties.insert(name, (false, schema.into()));
+        self.properties.insert(name, schema.into());
         self
     }
 
     pub fn optional<S: Into<Arc<Schema>>>(mut self, name: &'static str, schema: S) -> Self {
-        self.properties.insert(name, (true, schema.into()));
+        self.properties.insert(name, Arc::new(Schema::Option(schema.into())));
         self
     }
 }
@@ -296,6 +296,7 @@ pub enum Schema {
     String(StringSchema),
     Object(ObjectSchema),
     Array(ArraySchema),
+    Option(Arc<Schema>),
 }
 
 impl From<StringSchema> for Schema {
@@ -455,6 +456,9 @@ pub fn parse_simple_value(value_str: &str, schema: &Schema) -> Result<Value, Err
             string_schema.check_constraints(value_str)?;
             Value::String(value_str.into())
         }
+        Schema::Option(option_schema) => {
+            parse_simple_value(value_str, option_schema)?
+        }
         _ => bail!("unable to parse complex (sub) objects."),
     };
     Ok(value)
@@ -472,7 +476,7 @@ pub fn parse_parameter_strings(data: &Vec<(String, String)>, schema: &ObjectSche
     let additional_properties = schema.additional_properties;
 
     for (key, value) in data {
-        if let Some((_optional, prop_schema)) = properties.get::<str>(key) {
+        if let Some(prop_schema) = properties.get::<str>(key) {
             match prop_schema.as_ref() {
                 Schema::Array(array_schema) => {
                     if params[key] == Value::Null {
@@ -523,9 +527,14 @@ pub fn parse_parameter_strings(data: &Vec<(String, String)>, schema: &ObjectSche
     }
 
     if test_required && errors.len() == 0 {
-        for (name, (optional, _prop_schema)) in properties {
-            if *optional == false && params[name] == Value::Null {
-                errors.push(format_err!("parameter '{}': parameter is missing and it is not optional.", name));
+        for (name, prop_schema) in properties {
+            match prop_schema.as_ref() {
+                Schema::Option(_) => {},
+                _ => {
+                    if params[name] == Value::Null {
+                        errors.push(format_err!("parameter '{}': parameter is missing and it is not optional.", name));
+                    }
+                }
             }
         }
     }
@@ -554,6 +563,11 @@ pub fn verify_json(data: &Value, schema: &Schema) -> Result<(), Error> {
         Schema::Array(array_schema) => {
             verify_json_array(data, &array_schema)?;
         }
+        Schema::Option(option_schema) => {
+            if !data.is_null() {
+                verify_json(data, option_schema)?;
+            }
+        }
         Schema::Null => {
             if !data.is_null() {
                 bail!("Expected Null, but value is not Null.");
@@ -618,7 +632,7 @@ pub fn verify_json_object(data: &Value, schema: &ObjectSchema) -> Result<(), Err
     let additional_properties = schema.additional_properties;
 
     for (key, value) in map {
-        if let Some((_optional, prop_schema)) = properties.get::<str>(key) {
+        if let Some(prop_schema) = properties.get::<str>(key) {
             match prop_schema.as_ref() {
                 Schema::Object(object_schema) => {
                     verify_json_object(value, object_schema)?;
@@ -635,9 +649,14 @@ pub fn verify_json_object(data: &Value, schema: &ObjectSchema) -> Result<(), Err
         }
     }
 
-    for (name, (optional, _prop_schema)) in properties {
-        if *optional == false && data[name] == Value::Null {
-            bail!("property '{}': property is missing and it is not optional.", name);
+    for (name, prop_schema) in properties {
+        match prop_schema.as_ref() {
+            Schema::Option(_) => {},
+            _ => {
+                if data[name] == Value::Null {
+                    bail!("property '{}': property is missing and it is not optional.", name);
+                }
+            }
         }
     }
 
diff --git a/src/cli/command.rs b/src/cli/command.rs
index 87143d82..3c36e3da 100644
--- a/src/cli/command.rs
+++ b/src/cli/command.rs
@@ -120,7 +120,7 @@ fn record_done_arguments(done: &mut HashSet<String>, parameters: &ObjectSchema,
     for arg in list {
         if arg.starts_with("--") && arg.len() > 2 {
             let prop_name = arg[2..].to_owned();
-            if let Some((_, schema)) = parameters.properties.get::<str>(&prop_name) {
+            if let Some(schema) = parameters.properties.get::<str>(&prop_name) {
                 match schema.as_ref() {
                     Schema::Array(_) => { /* do nothing */ }
                     _ => { done.insert(prop_name); }
@@ -147,7 +147,7 @@ fn print_simple_completion(
             print_simple_completion(cli_cmd, done, &arg_param[1..], args);
             return;
         } else if args.len() == 1 {
-            if let Some((_, schema)) = cli_cmd.info.parameters.properties.get(prop_name) {
+            if let Some(schema) = cli_cmd.info.parameters.properties.get(prop_name) {
                 print_property_completion(schema, prop_name, &cli_cmd.completion_functions, &args[0]);
             }
         }
@@ -164,14 +164,14 @@ fn print_simple_completion(
         let last = &args[args.len()-1];
         if last.starts_with("--") && last.len() > 2 {
             let prop_name = &last[2..];
-            if let Some((_, schema)) = cli_cmd.info.parameters.properties.get(prop_name) {
+            if let Some(schema) = cli_cmd.info.parameters.properties.get(prop_name) {
                 print_property_completion(schema, prop_name, &cli_cmd.completion_functions, &prefix);
             }
             return;
         }
     }
 
-    for (name, (_optional, _schema)) in &cli_cmd.info.parameters.properties {
+    for (name, _schema) in &cli_cmd.info.parameters.properties {
         if done.contains(*name) { continue; }
         let option = String::from("--") + name;
         if option.starts_with(&prefix) {
diff --git a/src/getopts.rs b/src/getopts.rs
index 1293deec..4a276ca1 100644
--- a/src/getopts.rs
+++ b/src/getopts.rs
@@ -75,7 +75,7 @@ pub fn parse_arguments<T: AsRef<str>>(
                 None => {
                     let mut want_bool = false;
                     let mut can_default = false;
-                    if let Some((_optional, param_schema)) = properties.get::<str>(&name) {
+                    if let Some(param_schema) = properties.get::<str>(&name) {
                         if let Schema::Boolean(boolean_schema) = param_schema.as_ref() {
                             want_bool = true;
                             if let Some(default) = boolean_schema.default {
diff --git a/src/section_config.rs b/src/section_config.rs
index 0a057a73..c6a175f7 100644
--- a/src/section_config.rs
+++ b/src/section_config.rs
@@ -150,9 +150,14 @@ impl SectionConfig {
         let mut state = ParseState::BeforeHeader;
 
         let test_required_properties = |value: &Value, schema: &ObjectSchema| -> Result<(), Error> {
-            for (name, (optional, _prop_schema)) in &schema.properties {
-                if *optional == false && value[name] == Value::Null {
-                    return Err(format_err!("property '{}' is missing and it is not optional.", name));
+            for (name, prop_schema) in &schema.properties {
+                match prop_schema.as_ref() {
+                    Schema::Option(_) => {},
+                    _ => {
+                        if value[name] == Value::Null {
+                            return Err(format_err!("property '{}' is missing and it is not optional.", name));
+                        }
+                    }
                 }
             }
             Ok(())
@@ -204,7 +209,7 @@ impl SectionConfig {
                     if let Some((key, value)) = (self.parse_section_content)(line) {
                         //println!("CONTENT: key: {} value: {}", key, value);
 
-                        if let Some((_optional, prop_schema)) = plugin.properties.properties.get::<str>(&key) {
+                        if let Some(prop_schema) = plugin.properties.properties.get::<str>(&key) {
                             match parse_simple_value(&value, prop_schema) {
                                 Ok(value) => {
                                     if config[&key] == Value::Null {